This invention relates to breaking or crushing machines, particularly hammer crushers, which comprise a housing having a stationary wearing wall against which the material to be broken or crushed is beaten, ground, or otherwise smashed, usually by hammers mounted on a rotor which revolves within the housing.
The wearing wall is usually composed of a number of individual replaceable wearing plates which are removably fixed on the inside of the housing wall. However, the fixing of the wearing plates onto the housing wall of the machine poses certain problems, because the wearing plates are naturally subject to wear, whereas the fixing means are not. Therefore the most obvious way of fixing, namely that of screwing the wearing plates to the wall, is generally unsuitable because the screw connections also wear away as the plates wear and thereby lose their holding action.
Attempts have been made to overcome this fixing problem, and one example of such an attempt is disclosed in German Auslegeschrift No. 1,249,646. The solution proposed is however not completely satisfactory. In the fixing disclosed, an eyelet formed on the rear face of the wearing plate remote from the wearing surface projects outwards through an opening in the wall of the housing, and a wedge bearing against the wall is inserted into this eyelet. Screw connections are therefore avoided, but because the wearing plates are subjected to severe impacts, especially in the processing of materials which offer appreciable resistance to crushing, the wedges can sometimes become loose. It must be remembered that the wearing plates are components which are worn away and periodically must be replaced, and are therefore components for which a high manufacturing cost is unacceptable. Consequently the eyelets are not particularly accurately formed and it cannot be expected that the engaging surfaces of the wedges and eyelets will bear evenly one against another.